1. Field of the invention
The present invention generally relates to a tandem rotary electric machine in tandem mechanism or a rotary electric machine, equipped with a single rotor shaft and dual stator-rotor pairs, applicable to various applications, movable bodies such as vehicles.
2. Description of the Related Art
The following prior-art patent documents D1 to D3 have disclosed a rotary electric machine equipped with dual stator-rotor pairs (hereinafter, referred to as “a tandem rotary electric machine”), in which dual Lundel type rotors are assembled in a tandem mechanism, and which is capable of generating different voltages independently.    D1: Japanese patent laid open publication NO. JP H1-157251;    D2: Japanese patent laid open publication NO. JP H5-137295; and    D3: Japanese patent laid open publication NO. JP H5-308751.
Further, the prior-art patent document D4 has disclosed an electrical machine such as alternator for motor cars having a dual pole system cooperating with dual stator windings.    D4: U.S. Pat. No. 5,233,249 (corresponding to Japanese patent laid open publication NO. JP H5-500300).
Using the tandem mechanism with the Lundel type rotors can reduce the entire size of a rotary electric machine. Such a tandem rotary electric machine is capable of controlling the electricity generation to generate and output different voltages independently. In other words, the tandem rotary electric machine can be manufactured with a compact size at a relatively low manufacturing cost. Further, such a tandem rotary electric machine can reduce its mounting space in a vehicle when compared with the case where two different non-tandem rotary electric machines are mounted on a vehicle.
Such a tandem rotary electric machine is used as a dual-voltage rotary electric machine having a double-voltage power system capable of generating and supplying both a normal 12-volt power source widely used and a 42 volt power source as a high voltage.
Because a rectifier device is placed or arranged at the outer end of a secondary stator-rotor pair along the axis direction of such a tandem rotary electric machine, it is necessary to electrically connect the stator of a primary stator-rotor pair to the rectifier device through lead wires (hereinafter, referred to as “connection lead wires”).
The prior art patent document D2 has proposed to wire such connection lead wires on the outer peripheral end of the secondary stator-rotor pair along its radial direction.
The inventors according to the present invention have disclosed new stator-coil mechanism using a sequential segment joining type stator coil that is applicable to the rotary electric machine field. For example, following patent documents D5 to D12 have been disclosed. The sequential segment joining type stator coil can increase the occupancy or share rate of segment conductors (as a stator coil) in each slot, arrange the entire shape of the stator coil with a compact size, and thereby reduce the entire size of the rotary electric machine.    D5: Japanese patent laid open publication NO. JP 2004-048939;    D6: U.S. Pat. No. 6,774,528 and U.S. Pat. No. 6,995,492 (corresponding to Japanese patent laid open publication NO. JP 2004-048941);    D7: U.S. Pat. No. 6,979,926 and US publication No. 2006/0033394A1 (corresponding to Japanese patent laid open publication NO. JP 2004-064914);    D8: U.S. Pat. No. 6,825,589 (corresponding to Japanese patent laid open publication NO. JP 2004-048967);    D9: Japanese patent laid open publication NO. JP 2004-032987;    D10: U.S. Pat. No. 6,833,648 (corresponding to Japanese patent laid open publication NO. JP 2004-032882);    D11: US publication No. 2003/0233748A1 (corresponding to Japanese patent laid open publication NO. JP 2004-032884); and    D12 : U.S. Pat. No. 6,910,257 (corresponding to Japanese patent laid open publication NO. JP 2004-032890).
Recent trend in this rotary electric machine field needs to further reduce the entire size and weight of the rotary electric machine. However, because the tandem rotary electric machine tends to increase the longitudinal length along its axis direction, there is a strong demand to reduce the entire size and weight of the rotary electric machine.
Although the patent document D2 has disclosed the manner to wire the connection lead wires along the axis direction at the outer peripheral end of a secondary stator-rotor pair in the tandem rotary electric machine, this manner increases the volume or size of the rotary electric machine along the radial direction in order to keep the electrical insulation of the connection lead wires and further to achieve the mechanical protection and thermal protection against outer impact and shock. As a result, this manner decreases the degree of adaptation of the tandem rotary electric machine to various applications, in particular, to vehicles equipped with various types of vehicle engines.